题目:
Given a binary tree containing digits from 0-9
only, each root-to-leaf path could represent a number.
An example is the root-to-leaf path 1->2->3
which represents the number
123
.
Find the total sum of all root-to-leaf numbers.
For example,
1 / \ 2 3
The root-to-leaf path 1->2
represents the number 12
.
The root-to-leaf path 1->3
represents the number 13
.
Return the sum = 12 + 13 = 25
.
分析:
这就是一道对二叉树进行遍历的题目,总体来说还是比较简单。我用的是广度优先遍历。。(深度优先宝宝我不是咋会。。。。)维护两个数组(一个是二叉树左右子树的数组,另外一个是相应位置的结果),大概就是这样。
代码:
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int sumNumbers(TreeNode* root) {
if(root==NULL)return 0;
int res=0;
queue<int> tmpRes;
queue<TreeNode *> tmpLeaf;
tmpRes.push(res);
tmpLeaf.push(root);
while(tmpLeaf.size()!=0){
TreeNode* tmpRoot=tmpLeaf.front();
tmpLeaf.pop();
int tmp=tmpRes.front();
tmpRes.pop();
tmp=tmp*10+tmpRoot->val;
if(tmpRoot->left==NULL&&tmpRoot->right==NULL)res+=tmp;
if(tmpRoot->left){
tmpLeaf.push(tmpRoot->left);
tmpRes.push(tmp);
}
if(tmpRoot->right){
tmpLeaf.push(tmpRoot->right);
tmpRes.push(tmp);
}
}
return res;
}
};